Transporting elements, such as starwheels, are often used to transport containers in container treatment machines. These transporting elements often use container grippers to suspend containers vertically. The container grippers typically engage a container at a container region directly beneath the container mouth. In the case of a bottle, this container region is a neck ring.
Among the advantages of this gripping method are that containers that differ considerably in terms of shape and size can be still be transported by the same transporting element or by the container grippers thereon without having to perform any structural modifications, such as exchanging a container guide and/or format parts. The sole requirement is that the containers each have the same configuration at the container region beneath the container mouth.
In practice, however, it has been found that known customary container grippers are often not suitable for securely holding and transporting filled containers. The difficulty arises because a filled container is very heavy. This means that when the transporting element rotates very fast, there will be high centrifugal forces exerted on the containers. Because the containers are so heavy, these forces can tear the containers out of the container grippers.
On known solution to this problem is to configure the container grippers such that the container mounts thereof at least partially enclose the container portion at a radially outer region in relation to the rotation axis or machine axis of the transporting element. However, such container grippers are mechanically complicated and expensive.
Also known are container grippers having two gripper arms formed by legs of a clip-like gripper element and that form, between them a container holding region. Control cams that cooperate with the gripper arms are provided on the rotating transporting element. These control cams open and close the container grippers.